South Korea’s KF-21 jet faces delays as costs soar 30%

South Korea’s domestically developed KF-21 Boramae fighter jet program is confronting possible schedule setbacks as manufacturing costs have risen sharply above original estimates, according to a Yonhap News report citing defense procurement documents.

Costs jump by nearly 30%

The Defense Acquisition Program Administration (DAPA) said the second-phase “Block-II” production is now projected to cost 18.44 trillion won ($12.5 billion)—approximately 30% higher than the 2024 estimate of 14.24 trillion won. DAPA attributed the increase primarily to inflation, the weakening South Korean currency, and global supply chain disruptions. The KF-21 program, launched in 2015, aims to replace the country’s aging fleet of F-4 and F-5 fighters. The first prototype was unveiled in 2021.

Production delays under consideration

Under the initial “Block-I” phase, Seoul plans to produce 40 aircraft focused on air-to-air combat capabilities by 2028. The follow-on “Block-II” phase is intended to build 80 additional fighters equipped with long-range air-to-ground missiles by 2032. However, officials are reportedly considering postponing deployment schedules due to mounting costs. According to the report, authorities may delay delivery of the first 40 jets by one year to 2029, while the second batch could enter service two to three years later than planned.

Technical specifications

The supersonic fighter can reach speeds of up to Mach 1.81 and has a range of 2,900 kilometers (1,801 miles). It is equipped with advanced systems including an active electronically scanned array radar and is designed for future stealth upgrades. Türkiye, which is also developing its indigenous KAAN fighter jet, faces similar challenges in balancing costs, timelines, and technological sovereignty in the competitive global defense industry.